This invention relates to the recording or display of information from a multiplicity of television cameras positioned at different locations. It relates more particularly to a system for switching between the camera outputs so that the occurrences at the different locations can all be monitored quasi-continuously.
This invention is primarily directed to those applications where pictures of events occurring at many different locations are recorded on video tape for immediate or later display on a television screen. For example, many stores and banks position television cameras at several critical locations such as teller's cages, vault areas, check cashing windows, etc. Pictures from all of these locations are displayed on television monitors or recorded on video tape for later display in the event they are to be subsequently reviewed. Thus, if there is a holdup or a bad check is passed, the recorded pictures may help identify the culprits.
In some installations, the cameras operate independently, each having its own television recorder or monitor. Since several viewing locations are involved, such systems become quite expensive because of the required redundancy of recorders and other equipment.
There do exist some systems which provide automatic switching between camera outputs. However, such systems are disadvantaged for several reasons. In some cases, the switching causes the recorded pictures to roll or jitter, thereby lessening the effective duration of the view at each location. Also, in other systems, it is not immediately apparent from any given recorded picture from which camera it originated. Thus, if a particular picture depicts a holdup, for example, valuable time may be lost determining at which viewing location the holdup is progressing.
Finally, some prior systems tend to be quite complex and expensive and thus require an undue amount of maintenance which increases down time and reduces their value for security purposes.